Myrtaceae na cadeia do espinhaço: a flora do Parque Estadual do Itacolomi (Ouro Preto/Mariana) e uma análise das relações florísticas e da influência das variáveis geoclimáticas na distribuição das espécies

• Ano de defesa: 2011
• Autor(a) principal: Mariana de Oliveira Bunger
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais
• Palavras-chave em Português: Taxonomia vegetal Parque Estadual do Itacolomi (MG); Botânica; Quadrilátero Ferrífero (MG); Mirtacea
• Link de acesso: https://hdl.handle.net/1843/BUOS-8FPMY3

The Myrtaceae composes a pantropical plant family, with about 3800 species, distribuited among 130 genera, and is well represented in the some Brazilian formations as the semideciduous and ombrophilous forests and montane grasslands and shrublands, mainly on mountain chains of the Cerrado and Mata Atlântica domains. The Myrtaceae occurring in the mountainous areas are poorly known taxonomically and biogeographically, and many samples collected in floristic and phytosociological inventories remain undetermined in the herbaria collections. This represents an impediment to accurate assessments of risk of extinction of species, usually based on geographic information. The main goals of this study regard: i) a taxonomic treatment of the Myrtaceae species of the Itacolomi State Park (PEIT) (Chapter I) and ii) an evaluation of influence of the distance and geoclimatic variables on the geographic distribution of the species across the Espinhaço Range and adjacent mountains (Chapter II). For the taxonomic treatment, descriptions, identification keys and illustrations are presented. Collections were made in the PEIT from September 2009 to December 2010, regarding all plant typologies. The collected material was lodged at the BHCB herbarium, and duplicates were sent to OUPR. The BHCB, VIC, OUPR and RB herbaria were revised in order to search for additional information about the Myrtaceae species of the PEIT. In the phytogeographic study, nineteen surveys from the Espinhaço Range and other adjacent mountains were compiled. CCA and DCA were utilized to assess the relationships between geographic and climatic variables, and the flora composition. A cluster analyzis was used to assess the floristic links among the studied areas. The survey resulted in 45 species occurring in the PEIT, belonging to 11 genera: Blepharocalyx (1 sp.), Calyptranthes (1 sp.), Campomanesia (4 spp.), Eugenia (4 spp.), Marlierea (3 spp.), Myrceugenia (2 spp.), Myrcia (20 spp.), Myrciaria (1 spp.), Plinia (1 spp.), Psidium (3 spp.) and Siphoneugena (4 spp.). One new record for Minas Gerais flora was registered: Eugenia mosenii. The floristic database comprised 219 species, 54% of wich occurring in only one of the sampled localities. The higher similarities were found between Catolés and Pico das Almas (Is=0,57) and PEIT and Serra do Caraça (Is=0,55). Geographical distance showed to be important in the differentiation among areas (p=0,0009; r=-3452), therefore, the greater the distance, the smaller was the floristic similarity. Myrtaceae showed to be a sensitive group to the geoclimatic variables used (40,6%). The floristic groups found can be primarily explained by the phytogeographical domain that they were inserted. Altitude and precipitation proved to be important factors when analyzing Myrtaceae distribution across the contemplated localities.